Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine blade assembly for producing power. The turbine blade assembly typically includes a rotor assembly rotatable positioned in a turbine combustion case and having a plurality of turbine blades extending radially outward from the rotor assembly. The turbine engine also includes a plurality of stationary turbine vanes, which are also referred to as diaphragm airfoils, extending radially inward from the turbine combustor case. The turbine blades and turbine vanes are aligned into rows, or stages, and are positioned in alternating rows of vanes and blades. The turbine vanes are typically attached to a turbine combustion case via a hook fit, as shown in cross-section in FIG. 1. The hook fit releasably and securely attaches the turbine vanes within a turbine engine. During operation, the hooks fits are susceptible to wear due to vibration, heat, and other factors. For instance, a hook fit is typically worn in the areas shown in FIG. 1. Such wear negatively affects the safety and efficiency of a turbine engine in which the wear occurs.
Typically, such wear regions are repaired on turbine engines during outages in which other aspects of the turbine engine are repaired. The hook fits of a turbine engine are repaired by first removing the cover half of a turbine of the combustion turbine case to provide access to the internal aspects of the turbine engine. Once the cover half has been removed exposing the rotor assembly, the rotor assembly may be removed from the turbine engine. Removing the rotor assembly from the turbine engine typically takes about two weeks of time and costs about $500,000 per turbine engine. Once the rotor assembly is removed, the cover half is reassembled and the hook fits are repaired using a boring bar.
Conventionally, hooks fits of a turbine engine have been restored manually. For instance, personnel typically use handheld grinders to prepare the worn regions before material is welded to the regions. Once the worn region is prepared, personnel weld material to the worn regions and then manually work the added material into shape using manually controlled grinders. Thus, the quality and precision of the restoration process is limited by the skill, experience, and ability of the personnel operating the grinding equipment. Because the majority of the process is manually controlled, the restoration process lacks the necessary precision to restore the hook fits to their original shape consistently and in a cost efficient and time efficient manner. Thus, a need exists for a more precise, time efficient method of repairing a hook fit of a turbine engine.